1. Field of the Invention
This invention relates to improvements in physchological testing methods, and in particular to a method and apparatus for testing for brain dysfunctions in a human, and in particular a small child.
2. Description of the Prior Art
A number of methods and apparatus are disclosed in the prior art that are useful for performing physiological tests on individuals. Such methods and devices are disclosed in U.S. Pat. Nos. 3,357,115 (Kelley), 2,341,678 (Wickes), and 2,023,488 (Poppen). These methods and apparatus are generally designed to determine if the individual is suited to a particularly stressful occupation, which occupation involves responding correctly to a multitude of varied stimuli. Occupations which can be particularly stressful include, for example, those held by air traffic controllers, airplane pilots, astronauts, and submarine crew members.
These methods and devices, however, are not particularly helpful for testing for brain dysfunctions in children ranging in age from the very young to the sub-teens, for the following reasons. First, these tests are inherently complicated as they attempt to duplicate the complicated and stressful environment of the occupation. Thus, it is usually difficult to teach a child how to take the test, let alone expect the child to accurately respond to the stimuli provided thereby. Second these tests generally measure the persons ability to coordinate a variety of physiological factors, such as for example simple reaction time and visual perception, as would be required of an applicant for the aforementioned occupations. Thus the results of such tests would not distinguish between brain dysfunction (as tested by response time) and visual impairments.
Another prior art device, which includes more simply learned tasks and thus is more suited to testing children is disclosed in U.S. Pat. No. 3,579,865, issued to Norman K. Walker, the present applicant, said patent being incorporated herewith. The patent discloses a method and apparatus for measuring the effect of stress on the performance of a primary task while a secondary task is also provided to be performed by the human operator. The primary task (Zero Input Tracking Analyzer or ZITA) involves the use of a control stick to keep a light spot centered on a reference point. The control stick in one embodiment of that device has two positions, one position causing the light spot to travel to the left of the reference point, at a constant velocity, and the other position causing the light spot to travel to the right of the reference point at a constant rate. Velocity, acceleration, lag and/or lead functions can be selected to make the light spot travel at other than a constant velocity and thus make the centering task more difficult. As the control stick is always in one of the two positions, when the device is actuated, the light spot will automatically start traveling away from the reference point. Consequently, no initial input is needed and the human operator has only to null his own error from his previous response, i.e., center the light spot on the reference point.
The secondary task (Auxiliary Distraction Task or ADT) produces a "distraction stress" to the human operator while he is carrying out the primary task. This task requires that the human operator respond to the stimuli of high or low tones, presented to him by headphones, by moving another control stick forward or backward between two positions, for the high and low tones, respectively. Alternatively the operator could press push buttons to respond to the stimuli. A common display/recorder is used to record the performance on both tasks for analysis.
Studies have shown, however, that very small children do not have what can be described as a "center concept". This is to say, if a small child is asked to hold a dot of light in the center of a screen or on a reference point, the child will find to his delight that the spot of light will obey the commands of the control stick. The child can steer the light spot, but generally has no motivation to hold the spot on a reference point.
Further, the test results of the method and apparatus disclosed in this patent include a visual perception factor (following the spot of light with the eye) which can cloud evidence of some brain dysfunctions.